Thkee-phase wired radio receiving circuits



R. D. DUNCAN, JR

THREE-PHASE WIRED RADIO RECEIVING CIRCUITS Filed April 20, 1926 uvmvrox .fiaiemzflzuncarz :72:

' ATTORNEY Patented Apr. 14, 1931.

"amass. Duncan, #3., or EAST unmet;

new mm, assrenon, .BY MEsnE Assrem ori inal applicatien filed June 5, 1925, Seria1 No. 35,212, now Patent'ito.

, H 1: Divided and this application filed My it ventiOh, relates breedly iwave signaling systems and more particu- ,larly to a receivingsystem for carrienwave line wire operation. 5 I v 5 This application is a division of my Um ted ;States Patent N umber; 1,592,085, issued uly 13, 1926. I

One. of the provide a circuit arrangement for wired ra dlO receivingsystems whereby stray electrom ag- ..netic fields orradiation from the line. wires over which the high frequency currents are conveyed are substantiallynegligible there? by eliminating the inherent disadvantages which exist where wired radiolsignals' are .thrownopen to reception over, space radio :l y J a Anothe object of my-invention is to providea circuit arrangement for wired radio 9 receiving systems whereby a plurality of receiving apparatus connecting with the d1fferent phases of a polyphase transm ssion line greceive substantiallyequal amounts of high frequency energy by virtue of polyphase h1gh frequency transmission and of phaserevers iing circuits at the receivers. @Still another object of my i ventionis to provide a wired radio receiving system where received currentsj at a plurality of:re ce1v ing 0 stations connected along a carrienwave line wire distribution system may be effectively impressed upon translating circuits with. rela- .ti e y l rge g i y. b vir u JPPlY- phase transmission.

i sa a-San further an as Maia is to provide a receiving circuit arrangement ,for wired radio systems where the efl'ective energy impressedupon thetranslating c r- Qcuit maybe considerably augmented by ,transmittingand receiving three phase on r- ;rier waveenergy. 1 r

, gnientof inductances in coupledrelation at a ereoeiving station for o reversing the phases ofzpolyphase signaling currents that theseveral phases are vectoriall y added to effectively i operate he translati g, device at the wired ,iradio recelver ,QfQL,"v 1

"In-1n h1 fr" uency carrier current com.-

" manna-runes wrrinn iinnro RECEIVING crnourrs f 1 f P April 20,1926. Serial No. 103,339.

the high-frequency current imposed on electric lighting and power lines, it has been determined that when the latter forms. part of a three phase transmission system, which is the case in practically all of the modern'power systemsgthe generation and utilization of three phase high frequency current rather than single phase high frequency current is accompanied by a number ofadvantages. The principal advantages are. a'. uniform and even high frequency current-distribution over the power lines, and

the practical complete elimination of stray electromagneticfields or radiation from the lines. 1 The reason for the latter is that the currents inthe three phases-differ in phase by 120 degrees and in accordance with fundamental electrical theory at any instant their sum is zero or their combined effect upons {In my .Patent No. 1,578,881, dated March an-external receiver is nil. Y

.31, 1926, and. inmy co-pending application Serial N 0. 61,019, filed October 7 1925, and y United States Patent Number 1,643,405

issued September .27 ,"1927, l-have shown a.

vnew and novel method for generating high frequency current at polyphase and in par vticular ,three phase. In Letters Patent 1 1,560,505 dated November 3, 1925, I have illustrated 3 one of .the applications of poly-- .phase high frequency signaling systems using a high frequency current source simi.-' .lar to that whichmay be employed in my present system. *In long distancehigh volt- ,age power transmission three phasecarrien- 1,592,085, dated July.13, 1926,

current operation is especially beneficial. It .i c

; is; also possible by proper and suitable are Tangement of receiving apparatus to derive" additional benefits from three phase high 3 frequency operation. t t In the embodiment of the invention herein claimed a distinct advantage;is to be found over the invention covered by ,myPat- -g,ent1, 592,085.. This advantage residesin the discovery that the polyphasetreceiving cir-- cuit may be; coupled through only two windings with the'three'phase circuit which connects to the line-wire system. One ofthe 'coils infthe three phase line wire circuit is time?ssepl e j el ti eshir.Fails. Pails? 3 the receiving circuit proper and yet it is found that the currents in the several windings may be vectorially added to operate the responsive device.

Thus it is possible in carrying out the present invention to dispense with the coupling between the receiving circuit and one Of the. windings of the three phase tlflllSlIllSSlOIl system.

My invention will be more clearly understood by reference, accompanying wave system and in the wired radio receiving circuit which I provide for connection to the three phase transmission line.

Referring to the drawings in detail, reference character 1 in Fig. 1, represents a power house or substation; reference characters 2, 3 and 4 show three transmission lines forming a three phase power system leading from the power house 1 and reference letter 5 indicates a receiving power substation connected with the transmission line. Connected to the three lines 2, 3 and 4, through coupling condensers 6, 7 and 8, is a three phase high frequency generating source 9, which sup lies modulated high frequency current to tie lines. Suitable means are provided in association with the high frequency generating source 9 for effecting modulation by voiceor for forming telegraphic signals. Connected to the line through condensers 10, 11 and 12 at any desired points along the line adjacent the receiving end are inductance coils 13, 14' and 15 which-are shown to be inter'connected in star or Y. Inductively coupled to two ofthese coils, for example, 13 and 1.4, is a series circuit made up of inductance coils 16 and 17 and capacity 18. The capacity 18 may or may not be variable. Inductances 16 and 17' are substantially identical in construction and have approximately the same number of turns wound in the same direction. Coils 16 and 17 are connected in reverse manner, however, asillustrated. The receiving circuit contains a suitable translating device for observing the received signals. A crystal detector 19 is shown connected in the receiving circuit with telephone receivers 21 shunted by condenser 20. A

a The operation of the system as illustrated in Fig. 1 may be explained with the assistance of the vector diagrams of Figs, 2 and 3. The three phase high frequency signaling currents, modulated or unmo dulated, established in the lines 2, 3 and 4. by enerator 9,

cause to flow in the three phase out s 13, 14 and 15 three equal currents 1,, I 1,, differing in phase by 120 degrees as indicated in Fig. 2. The magnetic field established by coils 13 and 14 induce voltages in coils 16 and 17 which give rise to currents I and 1 The current I is displaced 180- degrees from I by virture of the reversed conct n of coil. 7 and t esp t. o s i .6- The r nt cu ren in ir uit 17 and 18 which may or may not be tuned to resonance, is the vector sum of I, and )L and is equal to B: or 1.732 times either 1 or )1, due. to. the fact that; th phase angle between these currents has been changed from 120 degrees to 60 degrees. The value ofthe effective current is therefore indicated at I which is the vector sum of 1 and (-)I This eflective current I" actuetes the translating circuit containing detector 19 and telephones 21.

By methods shown in Fig. 1, the use of three phase high frequency signaling energy for carrier operation over high voltage power lines is made possible with its accompanying advantages oi substantially non-radiation and increased signal strength which polyphase reception makes possible as compared with single phase reception. It will be observed that the eifeotive received current which actuates the translating circuit isrepresented by the vector I in 3 and that the value thereof is substantially greater than the current value' which could be efiectively secured by merely coupling the receiving circuit to the line in a single phase system. V It will be noted that a reversed connection is shown at inductance 17, Fig. 1 Itis obvious that an equivalent effect can be obtained with inductance 17, symmetrically connected, with the remaining inductances ofjthe circuit containing them, but with their direction of winding reversed from that of the remaining inductances. This change obviously falls within the scope of this invention, since'the essential requirement is that of'obtaining substantially a complete phase reversal of one of the component currents established in the circuit containing'ind'uctances 1 6 and-17 of Fig,- I. With regard to the theory of the; circuits shown, it should be noted that the reversed connection of'coil 17 is to obtain a complete phase reversal of the component of'current induced in this coil. This phasereversalfi may be accomplished eitherby reversal o5 connections as shown, or by symmetrical connection of the coils but reversed in the directionof winding of the same, as hereinbefore pointed out. By virtue of this reversal the resultant vectorcurrent of circuit 16;, 17 and 1810f Fig; 1 is substantially equal to 135 either of the individual component currents induced through coupling coils 13--16i'a.nd 1 1-17, said component currentsof course being equal under symmetrical conditions of coil construction and coupling;

While I have described my invention in a particular embodiment, I desire that it be understood that modifications may be made and that no limitations upon the invention are intended other than are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A wired radio communication system comprising a line circuit, for conveying three phase signaling energy, means including independent inductances connected to each 01 the phases of said line circuit, a translating circuit, said translating circuit including a pair of oppositely connected inductance coils, each coil being independently coupled to one of said inductances and a signal observing circuit connected with said translating circuit for vectorially adding the effect of the signaling energy.

2. A wired radio receiving system comprising a three phase electric power transmission line carrying superimposed three phase high frequency current, three substantially equal inductances, one of said inductances being connected in each phase of said transmission line, two additional inductances symmetrically coupled to two of said first mentioned inductances and connected in series in an opposing manner, the remaining of said first mentioned inductances being remote from coupled relationship with respect to said two additional inductances, a translating and signal indicating means associated with said additional inductances, the coupling between said additional and first mentioned inductances being such thatthe resultant current in said additional inductances is vectorially add- 1n A wired radio receiving circuit comprising in combination a three phase line wire circuit, an inductance connected to each phase of said line wire circuit, a polyphase receiving circuit, and a pair of coils disposed in said receiving circuit and coupled with two of said aforementioned inductances and arranged to vectorially add the current components in said polyphase receiving circuit for operating an indicator device, one of said first mentioned inductances being free of coupling relationship with said pair of coils.

4. A wired radio receiving system comprising in combination with a three phase line wire circuit, an inductance connected in each phase of said circuit, a three phase receiving circuit, a pair of coils connected with said three phase receiving circuit and coupled with all but one of the inductances in said line wire circuit, a rectifying device, a responsive device, and connections therebetween for vectorially adding the effects of current components in said three phase receiving circuit upon said recti 'ng device.

no ERT n. DUNCAN, JR. 

